Observe the major satellites of Jupiter and draw or photograph them then identify which each of them are. You can also follow this on consecutive nights and note (draw) how the positions of the Galilean Moons change from night to night.
Below are perfect examples of the requirements for the challenge. No notes were provided by Nathan.
This was part of the observing challenge for April completed by Nathan "Skully" Brookes.
Both images were created with images taken over a period of 3 hours then stacked to make Graphic Interface Files. (Gif's)